Description
The invention concerns an impact girder for vehicle doors, in particular for the doors of passenger cars, which is extruded from a light metal alloy and, extending in the vehicle door approximately in the direction of travel can be fixed at both ends in such a way that one profile wall of the impact girder faces towards the vehicle internal space as the inner flange and a second profile wall of the impact girder provided at a distance from the first forms an outer flange.
Such impact girders are known from DE-A-36 06 024 and are provided in the vehicle doors to protect the vehicle occupants against collision deformation forces acting transverse to the direction of travel, i.e. sideways. Although these impact girders can offer better shape stiffness against torsion during impact deformation compared with those of I-shaped cross-section of EP-A-0 063 325, they can however fracture occasionally in the case of very, large acceptance force.
In accordance with DE-A-37 09 489, impact girders are to be further improved in such a way that while having a low weight, they exhibit a large measure of shape retention with a sufficient capability to compensate for the deformation energy occurring and to take up, in the case of an impact, a controllable shape with the inner flange undamaged. For this purpose, the outer flange of the impact girder is provided, approximately in the middle of its length, with a pair of formed recesses at the edge. These relief notches act against the bending of the impact girder in the case of a side impact, which tends to fracture in the final phase of deformation in the case of very high elastic limit relationships.
The installation height of an impact girder in a vehicle door is generally above the bumper height of passenger cars. This has the result that in the case of a side impact, the door box below the impact girder is forced in without substantial energy absorption and that, in consequence, practically the whole of the deformation energy has to be accepted by the impact girder.